Zupanc G K, Airey J A, Maler L, Sutko J L, Ellisman M H
Department of Neurosciences, University of California, San Diego, La Jolla 92093.
J Comp Neurol. 1992 Nov 8;325(2):135-51. doi: 10.1002/cne.903250202.
The ryanodine receptor, an integral membrane protein of the sarcoplasmic reticulum in muscle, embodies a high conductance channel permeable to calcium ions. Recent studies have identified ryanodine-binding proteins in avian and mammalian central nervous systems. These neuronal ryanodine receptors appear to function as Ca2+ channels which may gate the release of Ca2+ from caffeine-sensitive intracellular pools in neurons. In the present investigation, we employed monoclonal antibodies against ryanodine-binding proteins of avian muscle cells to the brain of weakly electric gymnotiform fish. Immunoprecipitation and Western blot analysis revealed two isoforms in the fish brain, with molecular weights comparable to those of avian and fish muscle ryanodine-binding proteins. By employing immunohistochemical techniques, we mapped these proteins in fish brain. Ryanodine receptor-like immunoreactivity was found in nerve cell bodies as well as dendrites and axonal processes. The ryanodine-binding protein is distributed throughout the neuraxis in specific cell types of the gymnotiform brain. In the telencephalon, immunoreactive cells were found in the glomerular layer of the olfactory bulb, in the supracommissural subdivision of the ventral telencephalon, and in the intermediate rostral subdivision of the ventral telencephalon. In the diencephalon, immunoreactive cells or fibers were observed in the nucleus prethalamicus and the habenula, within the nucleus at the base of the optic tract and the adjacent dorsal tegmental nucleus, the pretectal nuclei A and B, and the nucleus electrosensorius. In addition, immunopositive cells were seen in several nuclei of the hypothalamus, with the inferior and lateral subdivision of the nucleus recessus lateralis displaying the highest concentration of neurons. In the mesencephalon, the optic tectum contained the greatest number of immunopositive cells. In the rhombencephalon, labelling was seen in the nucleus of the lateral valvula, central gray, lateral tegmental nucleus, in boundary cells of the nucleus praeminentialis, efferent octavolateral nucleus, an area adjacent to the medial edge of the lateral reticular nucleus, nucleus medialis, and electrosensory lateral line lobe. As in avian brain, cerebellar Purkinje cells were positive for ryanodine-binding protein, although only subsets of Purkinje cells were labelled.
兰尼碱受体是肌肉中肌浆网的一种整合膜蛋白，它是一种对钙离子具有高通透性的通道。最近的研究在鸟类和哺乳动物的中枢神经系统中发现了兰尼碱结合蛋白。这些神经元兰尼碱受体似乎起着钙离子通道的作用，可能控制着神经元中对咖啡因敏感的细胞内钙库释放钙离子。在本研究中，我们将针对鸟类肌肉细胞兰尼碱结合蛋白的单克隆抗体应用于弱电裸背电鳗目鱼类的大脑。免疫沉淀和蛋白质印迹分析显示，鱼脑中存在两种异构体，其分子量与鸟类和鱼类肌肉兰尼碱结合蛋白的分子量相当。通过免疫组织化学技术，我们在鱼脑中定位了这些蛋白。在神经细胞体以及树突和轴突中发现了兰尼碱受体样免疫反应性。兰尼碱结合蛋白分布于裸背电鳗目鱼类大脑特定细胞类型的整个神经轴中。在端脑，在嗅球的肾小球层、腹侧端脑的连合上部分以及腹侧端脑的中间吻侧部分发现了免疫反应性细胞。在间脑，在前丘脑核和缰核、视束基部的核以及相邻的背侧被盖核、顶盖前核A和B以及电感觉核中观察到了免疫反应性细胞或纤维。此外，在下丘脑的几个核中也发现了免疫阳性细胞，外侧隐窝核的下部和外侧部分神经元浓度最高。在中脑，视顶盖含有最多的免疫阳性细胞。在菱脑，在外侧瓣膜核、中央灰质、外侧被盖核、前庭前核的边界细胞、传出八侧线核、与外侧网状核内侧边缘相邻的区域、内侧核和电感觉侧线叶中发现了标记。与鸟类大脑一样，小脑浦肯野细胞对兰尼碱结合蛋白呈阳性，尽管只有部分浦肯野细胞被标记。
